Real-time estimation of daily physical activity intensity by a triaxial accelerometer and a gravity-removal classification algorithm

作者：Kazunori Ohkawara, Yoshitake Oshima, Yuki Hikihara, Kazuko Ishikawa‐Takata, Izumi Tabata, Shigeho Tanaka · 发表于：British Journal Of Nutrition · 年份：2011 · DOI：10.1017/s0007114510005441 · 被引用次数：478 · 研究领域：Physical Activity and Health、Obesity, Physical Activity, Diet、Context-Aware Activity Recognition Systems

We have recently developed a simple algorithm for the classification of household and locomotive activities using the ratio of unfiltered to filtered synthetic acceleration (gravity-removal physical activity classification algorithm, GRPACA) measured by a triaxial accelerometer. The purpose of the present study was to develop a new model for the immediate estimation of daily physical activity intensities using a triaxial accelerometer. A total of sixty-six subjects were randomly assigned into validation (n 44) and cross-validation (n 22) groups. All subjects performed fourteen activities while wearing a triaxial accelerometer in a controlled laboratory setting. During each activity, energy expenditure was measured by indirect calorimetry, and physical activity intensities were expressed as metabolic equivalents (MET). The validation group displayed strong relationships between measured MET and filtered synthetic accelerations for household (r 0·907, P < 0·001) and locomotive (r 0·961, P < 0·001) activities. In the cross-validation group, two GRPACA-based linear regression models provided highly accurate MET estimation for household and locomotive activities. Results were similar when equations were developed by non-linear regression or sex-specific linear or non-linear regressions. Sedentary activities were also accurately estimated by the specific linear regression classified from other activity counts. Therefore, the use of a triaxial accelerometer in combination with a GRP...